Vehicle driver assist arrangements, such as curve speed warning arrangements, have been available in cars for some years. Such arrangement may be capable of issuing a warning to a driver of a vehicle if the vehicle approaches a curve with a speed being too high to pass the curve in a pleasant or safe manner. Input to such arrangements may for example be data from a positioning system together with data from an electronic map, and when it is determined that a curve in front of a vehicle, having a certain velocity, either will result in an unpleasant passing or dangerous passing of the curve, a warning will be issued to the driver. Such an arrangement is for example described in the document GB 2413884 A. A problem with such an arrangement is that the issuance of the warning by the arrangement is not very accurate. That is, such systems tends to either issue a warning too often, and thus tends to annoy the driver which may even adjust the arrangement such that the warning will not be issued that often, or may even shut off the arrangement. Those skilled in the art easily recognizes the hazard with such arrangements since the arrangements in a potential dangerous situation may either warn too late or even not warn at all. Thus, there is a need for an arrangement that overcomes the above described shortcomings with the prior-art arrangements to thereby improve driving safety.